ASTM D5356-93(2009)

Standard Test Method for PH of Chrome Tanning Solutions

SIGNIFICANCE AND USE
This test method is designed to measure the pH of a chrome tanning solution which has been diluted to a specific concentration. This is considered to be a measure of the acidity or alkalinity of the solution.
This test method is suitable for quality control in the manufacture of leather.
SCOPE
1.1 This test method covers the determination of the pH of chrome tanning solutions.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 31-Mar-2009
• ICS: 59.140.40 - Machines and equipment for leather and fur production
• Technical Committee: D31 - Leather
• Drafting Committee: D31.06 - Chemical Analysis

Relations

• Replaces: ASTM D5356-93(2003) - Standard Test Method for PH of Chrome Tanning Solutions
• Effective Date: 01-Apr-2009
• Replaced By: ASTM D5356-10 - Standard Test Method for PH of Chrome Tanning Solutions
• Effective Date: 01-Nov-2010

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D5356–93 (Reapproved 2009)
Standard Test Method for
pH of Chrome Tanning Solutions
This standard is issued under the fixed designation D5356; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 5. Significance and Use
1.1 This test method covers the determination of the pH of 5.1 This test method is designed to measure the pH of a
chrome tanning solutions. chrome tanning solution which has been diluted to a specific
1.2 The values stated in SI units are to be regarded as concentration.This is considered to be a measure of the acidity
standard. No other units of measurement are included in this or alkalinity of the solution.
standard. 5.2 This test method is suitable for quality control in the
1.3 This standard does not purport to address all of the manufacture of leather.
safety concerns, if any, associated with its use. It is the
6. Apparatus
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- 6.1 pH Meter, either battery or line-operated equipped with
appropriate electrodes. The meter shall have a maximum scale
bility of regulatory limitations prior to use.
division of 0.1 pH unit and reproducibility of 0.05 pH unit.
2. Referenced Documents
NOTE 1—Sellers list reasonably priced models having more sensitivity
2.1 ASTM Standards:
and greater reproducibility.
D3898 Test Method for Chromic Oxide in Basic Chromium
7. Reagents
Tanning Liquors
E70 Test Method for pH of Aqueous Solutions With the
7.1 Purity of Reagents—Reagent grade chemicals shall be
Glass Electrode
used in all tests. Unless otherwise indicated, it is intended that
all reagents shall conform to the specifications of the Commit-
3. Terminology
tee onAnalytical Reagents of theAmerican Chemical Society,
3.1 Definition of Terms Specific to This Standard:
where such specifications are available. Other grades may be
3.1.1 pH, of a solution—the negative logarithm of the
used, provided it is first ascertained that the reagent is of
hydrogen ion activity.
sufficiently high purity to permit its use without lessening the
3.1.1.1 Discussion—A solution of pH 7 is neutral at 24°C.
accuracy of the determination.
Lower numbers indicate increasing acidity, higher numbers
7.2 Purity of Water—Unless otherwise indicated, references
indicate increasing alkalinity.
to water shall be understood to mean distilled water or water of
equal purity.
4. Summary of Test Method
7.3 Buffer Solutions—Commercially available buffer solu-
4.1 The chrome tanning liquor is diluted to a concentration
tions of 2.00 6 0.02 pH and 4.00 6 0.02 pH shall be used for
of 25.0 6 0.5 g chromic oxide equivalent per litre, allowed to
meter standardization, in accordance with the manufacturer’s
come to equilibrium and the pH is then measured with the
recommendations and the provisions set forth in Test Method
appropriate meter. For general details of a procedure, Test
E70.
Method E70 should be consulted. The provisions of the
standard shall be governing except where the text of this test 8. Standardization
method specifically deviates.
8.1 Standardize the meter against the pH 4.00 standard, in
accordance with the manufacturer’s recommendations and the
provisions set forth in Test Method E70. The buffer standard
This test method is under the jurisdiction ofASTM Committee D31 on Leather
and is the direct responsibility of Subcommittee D31.06 on Chemical Analysis
Current edition approved April 1, 2009. Published July 2009. Originally
approved in 1993. Last previous edition approved in 2003 as D5356 – 93 (2003). Reagent Chemicals, American Chemical Society Specifications , American
DOI: 10.1520/D5356-93R09. Chemical Society, Washington, DC. For suggestions on the testing of reagents not
For referenced ASTM standards, visit the ASTM website, www.astm.org, or listed by the American Chemical Society, see Analar Standards for Laboratory
contact ASTM Customer
...